The present application claims priority to Japanese Application(s) No(s). P2001-045271 filed Feb. 21, 2001, which application(s) is/are incorporated herein by reference to the extent permitted by law.
1. Field of the Invention
The present invention relates to an inkjet head and an inkjet printer, and, more particularly, to an inkjet head and an inkjet printer in which, by providing a cleaning member at a head cap for protecting an ink discharge surface, the body of the printer is reduced in size.
2. Description of the Related Art
Technologies for cleaning an ink discharge surface of an inkjet head with a cleaning member in a related inkjet printer are disclosed in, for example, Japanese Unexamined Patent Application Publication Nos. 57-61574 and 6-255117.
In the technology disclosed in Japanese Unexamined Patent Application Publication No. 57-61574, a serial-type inkjet head is used. This inkjet head reciprocates as a result of being guided in the widthwise direction of a recording sheet by a guide mechanism. In addition, a cleaning roller including an ink absorption layer at its peripheral surface and being rotatably held is provided between a location where photographic printing or printing on the recording sheet is started and a head accommodation location situated outwardly of one side of the recording sheet in the widthwise direction thereof. The ink discharge surface of the inkjet head is cleaned by causing it to come into contact with the cleaning roller when the inkjet head reciprocates when the printing operation starts and ends.
In the technology disclosed in Japanese Unexamined Patent Application Publication No. 6-255117, an inkjet head is formed with a length that allows it to cover the entire width of a recording sheet, and is secured above a transportation path of the recording sheet. An ink-discharge hole is provided in the inkjet head in correspondence with the entire width of the recording sheet. A cleaning roller which rotates while it contacts the entire length of an ink discharge surface of the inkjet head is provided. The cleaning roller is formed of a circular cylindrical resilient material and has a plurality of grooves formed in the outer peripheral surface thereof so as to extend in the axial direction. This cleaning roller is brought into contact with the ink discharge surface of the inkjet head, and rotates while it moves in a parallel direction, with the direction of rotation being in the direction of parallel movement, in order to hold ink in the plurality of grooves, so that the ink discharge surface is cleaned.
In inkjet printers, when photographic printing or printing by the inkjet head is not carried out for a long period of time, ink inside an ink discharge hole of the inkjet head undergoes evaporation drying, thereby resulting in increased viscosity or solidification of the ink, so that it becomes difficult to perform a proper ink discharge operation. In order to prevent this, a xe2x80x9cpreliminary discharge operationxe2x80x9d is carried out at a predetermined time interval or prior to photographic printing or printing in order to subject the ink inside the ink discharge hole to a refreshing operation by, for example, sucking and discharging the ink inside the ink-discharge hole at a predetermined location inside the printer. Such a technology is disclosed in, for example, Japanese Unexamined Patent Application Publication No. 10-278299.
However, in the technology disclosed in Japanese Unexamined Patent Application Publication No. 57-61574, it is necessary to provide the cleaning roller and the inkjet head accommodation location outwardly of one side of a recording sheet in the widthwise direction thereof, so that the size of the printer body in the widthwise direction thereof is increased. In addition, since the cleaning roller is affixed inside the printer body, replacement of the cleaning roller is not easy to carry out and the inside of the printer body may get contaminated because a receiving section for receiving ink which may get spattered during the cleaning of the inkjet head is not provided.
The place where a preliminary discharge operation for subjecting ink inside a ink discharge hole of the inkjet head to a refreshing operation is carried out is situated outwardly of the width of the recording sheet in the direction in which the inkjet head reciprocates, that is, the widthwise direction of the recording sheet. Therefore, a preliminary discharge ink receiving section must be provided at this location. Consequently, as expected, the size of the printer body in the widthwise direction thereof is increased. In addition, since the preliminary discharge ink receiving section is provided so that it cannot be easily mounted and dismounted, it is difficult to, for example, clean it.
In the technology disclosed in Japanese Unexamined Patent Application Publication No. 6-255117, the cleaning roller having a plurality of grooves formed in the outer peripheral surface thereof is brought into contact with the ink discharge surface of the inkjet head, and rotates while it moves in a parallel direction, with the direction of rotation being in the direction of parallel movement. Therefore, although the cleaning performance of scooping up the ink that has adhered to the ink discharge surface is high, there were instances in which the performance of the inkjet head got affected due to wearing of a resin protective layer of an electrode provided at the ink discharge surface. Edges are formed at the grooves of the cleaning roller. Since, by the rotation of the cleaning roller in the direction of movement of the cleaning roller, the edges wear quickly, the cleaning performance is reduced, so that it is difficult to maintain the cleaning performance of the initial condition of the cleaning roller for a long period of time.
Since the ink in the plurality of grooves has no place to go, the cleaning member can no longer provide cleaning performance when the grooves are filled completely with the ink, so that, thereafter, cleaning cannot be performed. In addition, since the cleaning roller is fixed inside the body of the printer, replacement of the cleaning roller is not easy to carry out and the inside of the printer body may get contaminated because a receiving section for receiving ink which may get spattered during the cleaning of the inkjet head is not provided.
Since the inkjet head is formed with a length that allows it to cover the entire width of a recording sheet, and is fixed above a transportation path of the recording sheet, when the place where a preliminary discharge operation for subjecting the ink inside the ink-discharge hole of the inkjet head to a refreshing operation is carried out is situated outwardly of the width of the recording sheet, a preliminary discharge ink receiving section and means for moving the inkjet head in the widthwise direction of the recording sheet must be separately provided at this location. Therefore, the size of the printer body in the widthwise direction becomes large or roughly twice the width of the recording sheet.
Accordingly, in order to overcome such problems, it is an object of the present invention to provide an inkjet head and an inkjet printer which are constructed so as to reduce the size of a printer body by providing a cleaning member at a head cap for protecting an ink discharge surface.
In order to achieve this object, according to one aspect of the present invention, there is provided an inkjet head comprising a head cap, which moves relative to and is removably mounted to a print head, for protecting an ink discharge surface of the print head; and a cleaning member, provided at a print-head side of the head cap in a longitudinal direction of the print head, for cleaning the ink discharge surface of the print head.
By virtue of such a structure, the ink discharge surface of the print head is protected by the head cap that moves relative to and is removably mounted to the print head, and, using the cleaning member provided at the print head side of the head cap in the longitudinal direction of the print head, the ink discharge surface of the print head is cleaned.
When the structure of the one aspect is used, an ink receiving section for receiving ink preliminarily discharged from an ink discharge hole may be provided at an inner side of the head cap.
By this, the ink preliminarily discharged from the ink discharge hole is reliably held in the ink receiving section of the head cap.
When the structure of the one aspect is used, means for detecting a timing of preliminary discharge from an ink discharge hole of the print head when the head cap moves relative to the print head may be provided at either an ink cartridge or the head cap.
By this, using the detecting means provided at either the ink cartridge or the head cap, it is possible to detect the timing of the preliminary discharge from the ink-discharge hole of the print head when the head cap moves relative to the print head.
When the structure of the one aspect is used, the cleaning member may be formed so as to have a circular cylindrical shape that comes into contact with the entire length of the ink discharge surface of the print head, and may be removably held by the head cap.
By this, the cleaning member removably held by the head cap and formed with a circular cylindrical shape is brought into contact with and cleans the entire length of the ink discharge surface of the print head.
When the cleaning member is formed so as to have a circular cylindrical shape that comes into contact with the entire length of the ink discharge surface of the print head, and is removably held by the head cap, means for biasing the cleaning member towards the ink discharge surface of the print head may be provided at a portion where the cleaning member is held by the head cap.
By this, using the biasing means provided at a portion where the cleaning member is held by the head cap, it is possible to bias the cleaning member towards the ink discharge surface of the print head.
When an ink receiving section for receiving ink preliminarily discharged from an ink discharge hole is provided at an inner side of the head cap, means for preventing the preliminarily discharged ink from being spattered back may be provided at a receiving surface of the ink receiving section.
By this, using the spattering-back preventing means provided at the receiving surface of the ink receiving section, it is possible to prevent the ink preliminarily discharged towards the ink receiving section from spattering back.
According to another aspect of the present invention, there is provided an inkjet printer comprising an inkjet head including an ink cartridge for holding ink of one color or of a plurality of colors therein, a print head including an ink discharge surface including an ink discharge hole for discharging ink supplied from the ink cartridge, a head cap, which moves relative to and is removably mounted to the print head, for protecting the ink discharge surface of the print head, and a cleaning member, provided at a print-head side of the head cap in a longitudinal direction of the print head, for cleaning the ink discharge surface of the print head; a head mounting-and-dismounting mechanism for mounting and securing the inkjet head to a predetermined location of a printer body and for dismounting the inkjet head from the predetermined location of the printer body; and a head cap placing-and-removing mechanism for uncovering the ink discharge surface and for placing the head cap after completion of a printing operation by, with the inkjet head being secured to the predetermined location of the printer body, moving the head cap relative to the print head.
By such a structure, using the head mounting-and-dismounting mechanism, the inkjet head is mounted to and dismounted from a predetermined location of the printer body. Using the head cap placing-and-removing mechanism, while the inkjet head is mounted to the predetermined location of the printer body, the head cap is moved relative to the print head in order to uncover the ink discharge surface and to place the head cap after completion of a printing operation. Using the inkjet head including the ink cartridge, the print head, the head cap, and the cleaning member, ink is formed into very fine particles and the very fine particles are discharged in order to blow ink dots onto a recording sheet, whereby printing is performed.
The inkjet printer may further comprise an ink receiving section, provided at an inner side of the head cap of the inkjet head, for receiving ink preliminarily discharged from the ink discharge hole.
By this, the ink preliminarily discharged from the ink-discharge hole is reliably held at the ink receiving section of the head cap.